1. Technical Field
The illustrative embodiments generally relate to accident mitigation. More specifically, the illustrative embodiments generally relate to curve-related-accident mitigation.
2. Background Art
The instances of single vehicle roadway crashes comprise approximately 20 percent of all light vehicle crashes annually in the U.S. Within the single vehicle roadway departure crash category, crashes may generally result from four basic categories:                Lane drifting        Loss of control        Evasive maneuvers        Driver incapacitation        
Countermeasures that attempt to address these crash categories may be derived from a variety of driver support systems.
Lane departure warning (LDW) and lane keeping assist (LKA) are conventionally addressed by computer vision through lane tracker detection that performs well when the vehicle is slowly drifting toward or across the lane marks. If the road geometry information is available through, for example, a digital map, the road edge might be calculated by computing a vehicle's deviation from the lane marks. Hence lane tracker based countermeasures can be used for mitigating certain road departure accidents. However there are two primary non-coverage issues that may occur in lane tracker based countermeasures. The first is due to not always being able to visually track the lane markers. The other issue occurs in the situation where the vehicle crosses the road edge with high lateral speed during high speed driving such that a warning or assist may be of little use to the driver.
Electronic stability control (ESC) can also be thought as a countermeasure for run-off-road accidents. ESC may help overcome the aforementioned non-coverage issues in lane mark based countermeasures: ESC uses the path determined from the driver's intent as the “virtual lane”, which may eliminate the dependency on the lane tracker detection for run-off-road. ESC may use motion sensors to determine the high lateral velocity or sideslip situation where the vehicle deviates from the path determined from the driver's intended path and uses electronic chassis controls such as brake controls to correct the vehicle's path deviation. Such control actions can be conducted in several tens of milliseconds, hence, ESC can react very quickly and respond to high dynamic driving condition changes.
While ESC overcomes the lane tracker and reaction time issues, it generally assumes that the driver's intent is correct. If the driver is making a wrong decision, ESC will not be very effective in mitigating potential run-off-road accidents. However, lane tracker-based countermeasures (LDW and LKA) and the driver-intent-based countermeasure (ESC) might be complementary. Integrating both types of measures might generate countermeasures that can cover more crashes than each of the countermeasures can handle individually.
These types of countermeasures are integrated together in the illustrative embodiments to mitigate speeding related curve-driving crashes. The embodiments can be similarly expanded to other crash scenarios. Each year from 1983 to 2002, about 14,000 persons (about 30% of all motor vehicle traffic fatalities) were killed in speeding-related crashes.
Besides run-off-road accidents, there are other potential crash scenarios that could happen on over-speeding in a curve, including                crashing into medians, guide rails, or the other stationary objects;        crashing with other moving vehicles;        on-road rollovers; and        multiple event accidents.        
Those crash scenarios are potentially due to, for example:                a driver's panicked actions;        a high kinematical energy of the vehicle;        a demand of fast reaction time due to high speed; and        a driver's inability to adapt to sudden condition change through improvisation.        
It is desirable to find electronic control functions to mitigate the curve-over-speed crashes. One example of a way to do this is to integrate driver-intent based stability control with lane tracker based vehicle control.